<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>固定高度</title>
    <style>
        .one{
            height:204px;
            border:2px dashed green;
        }
        .left{
            width:200px;
            height:200px;
            float: left;
            border:2px solid red;
        }

    </style>
</head>
<body>
    <div class="one">
        <div class="left">我是浮动的</div>
    </div>
</body>
</html>
